Cellulose-based products made from cellulosic fibers, chips, and shavings make up a significant portion of the building product market because they are cost effective, easy to work with, and environmentally friendly. Cellulose-based products provide structural support, act as roofing substrates, and dampen unwanted noise. Unfortunately, traditional cellulose-based products are also flammable. A number of methods have been developed to reduce the flammability of such materials, but many current methods are inadequate at providing fire-retardancy, are too expensive, or have some other shortcoming.
For example, U.S. Pat. No. 6,518,333 issued to Liu et al., on Feb. 11, 2003, teaches a fire-retardant cellulosic product comprising: a cellulosic material, at least one polymeric binder resin, and fire retardant solid particles compressed together to form a panel. While products produced according to Liu have some degree of fire-retardancy, they fail to qualify for the Class A rating for ASTM E-84. Furthermore, products that use polymeric resins can sometimes create toxic off gases when exposed to flames for extended periods time.
U.S. Pat. No. 5,840,105 issued to Helmsetter et al., on Nov. 24, 1998, discloses a fire-resistant solution for application to the surface of cellulosic materials comprising: water, pure white clay, fine mica and sodium silicate. Surface coatings like that described in Helmsetter '105 provide flame resistance to the surface of cellulosic materials, however, they fail provide full depth fire protection.
A need exists for a method that provides reliable full-depth fire-retardancy to cellulose-based particle products that is cost effective, and is non-toxic.